1. Field of the Invention
This invention is in the field of water recirculation systems. 2. Description of the Prior Art
A typical hot and cold running water system, such as is found in residential homes, does not include any means for recirculating the hot water from the vicinity of the hot water faucet back to the water heater. This is because the pipes are short enough that upon opening the faucet, sufficient flow is obtained that undue waiting is not necessary before hot water is available at the tap. In commercial establishments and apartment buildings, sometimes the location of the hot water heater for the hot water system is quite remote from some or all of the locations at which hot water is to be used.
One solution to this situation in the past has been the provision of a recirculating pump which continuously moves hot water from the vicinity of the individual taps being utilized by the user back to the water heater so that hot water is continuously available near each of the taps.
The difficulty with this solution to the hot water distribution problem is that it utilizes an excessive amount of energy for the continuous operation of the recirculating pump during times when hot water is not desired at remote locations. A further drawback to this operation is that heat is lost as the hot water is circulated through the pipe distribution system, requiring the expenditure of still more energy by the water heater to return the recirculated water to a proper hot water temperature. One further difficulty which has been encountered in some cases is the effect of the heat losses of the hot water piping to the extent that the floor of the building and even the adjacent cold water pipes are heated excessively by the recirculated hot water in the hot water pipes. Thus, while hot water is continuously available at the hot water faucets, it is extremely difficult to obtain cold water without a long delay since all or much of the water standing in the cold water pipes is heated by the recirculated hot water.
Certain water recirculation systems of which the applicant is aware, though not adapted for use in the presently disclosed apparatus, include those shown in U.S. Pat. Nos. 2,763,281 to Morgan; 2,981,195 to Payne II et al; and 3,786,835 to Finger. Another nonrelated water recirculation system is shown, with a timer mentioned therein, in U.S. Pat. No. 3,639,081 to Gray et al.